I just had a Zone 6" lift put on a 2000 Yukon Xl
They say it retains the factory ride, I have to say they are pretty close.
I also installed a ranch hand legend Grille Guard, MT baja ATZ 35's and pro comp wheels.
I drove it down Highway 17 from Santa Cruz to the bay area and it felt very similar to stock (except for sitting 11" higher)
I would recommend Zone lifts to everybody...
One problem I have found is that the 35's are rubbing in the front, at the back side of the tire. (on the inner fender) I'm sure this is a problem with most 6" lifts and 35's, but figured I should throw it out there.
Here are some pics.